Neutrons can be detected to indicate the presence of special nuclear materials, such as plutonium, or to be used in neutron imaging. An example of a neutron detector is a neutron-sensitive microchannel plate (MCP). An MCP can be formed by bonding a glass plate between an input electrode and an output electrode, and providing a high voltage direct current (DC) field between the electrodes. The glass plate is perforated with a substantially regular, parallel array of microscopic channels, e.g., cylindrical and hollow channels. Each channel, which can serve as an independent electron multiplier, has an inner wall surface formed of a semi-conductive and electron emissive layer.
The MCP can be made neutron-sensitive by doping the glass plate with, e.g., boron-10 particles, which can capture neutrons in reactions that generate lithium-7 and alpha particles. As the lithium-7 and alpha particles enter nearby channels and collide against the wall surfaces to produce secondary electrons, a cascade of electrons can be formed as the secondary electrons accelerate along the channels (due to the DC field), and collide against the wall surfaces farther along the channels, thereby increasing the number of secondary electrons. The electron cascades develop along the channels and are amplified into detectable signals that can be electronically registered and sometimes processed to construct an image. The resultant intensity map or image corresponds to the variation in neutron flux striking the surface of the MCP. Contrast differences within the image of a sample can be used to infer physical and chemical properties.